100% Private
All text comparison happens in your browser. Your content never leaves your device or gets uploaded to any server.
Browser tool● Processed in your browser
Diff Checker
Compare two texts side by side and instantly spot additions, deletions, and unchanged lines. Free, private, and runs entirely in your browser.
01 · Guide
How it works
- 01
Paste your original text in the left panel
- 02
Paste the modified text in the right panel
- 03
Click "Compare" to run the diff analysis
- 04
Review highlighted additions (green), deletions (red), and unchanged lines
Why use this tool
Line-by-Line Comparison
Uses an LCS-based diff algorithm for accurate line-by-line comparison with clear visual highlighting.
Detailed Statistics
See a summary of lines added, removed, and unchanged at a glance to understand the scope of changes.
Whitespace Options
Toggle whitespace-aware comparison to ignore or include trailing spaces and indentation differences.
Frequently asked questions
What diff algorithm does this tool use?+
It uses a Longest Common Subsequence (LCS) based algorithm for line-by-line comparison, providing accurate results similar to professional diff tools.
Is my text uploaded to a server?+
No. All comparison is performed entirely in your browser using JavaScript. Your text never leaves your device.
Can I ignore whitespace differences?+
Yes. Toggle the "Ignore whitespace" option to skip differences caused by spaces, tabs, or trailing whitespace.
Is there a size limit for the text?+
There is no hard limit, but very large files (over 50,000 lines) may cause slower performance since everything runs in the browser.
Can I swap the original and modified texts?+
Yes. Use the "Swap" button to instantly switch the contents of the left and right panels.
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